Gasification is a technique to produce combustible gas fuel from solid fuel, which has a very long history and is still being developed. The fuel that human beings have used has changed from trees, coal, gas, oil, electricity and so on, some of which are still used for cooking and heating.
Carbon fuel (generally referred to as coal, divided into bituminous coal, sub bituminous coal, brown coal, anthracitic coal and the like) has been used for industrial purposes since the late eighteenth century, when the Industrial Revolution in Britain began. Historically, charcoal was replaced with coke as a reducing agent for the metal industry, or coal was used for city gas. Combustible gas fuel obtained as a result of gasifying carbon fuel is referred to as synthesis gas, which means that it is artificially produced, and is distinguished from natural gas which is natively embedded under the ground of the earth. Initially, synthesis gas has been used for city street lights, and then used for replacing solid fuel or producing chemical fuel. Recently, it is used for generating power or producing synthesis fuel.
In this connection, U.S. patent application Ser. No. 12/737,823 (filed on Aug. 13, 2009), entitled “Device for Gasification of Carbonaceous Fuels”, discloses a device for gasification of carbonaceous fuels.
The gasification of carbon fuel produces synthesis gas consisting mainly of hydrogen and carbon monoxide by the oxidation reaction of carbon fuel while an oxidizing agent supplied to a reactor, and by the oxidation-reduction reaction of the carbon fuel with gas generated in the reactor such as carbon dioxide, steam and hydrogen.
The synthesis gas thus obtained is hot gas, and may be used for the integrated gasification combined cycle (IGCC) or the Fischer-Tropsch process, in which a heat exchanger for cooling the hot synthesis gas down to a certain temperature is essentially required.
Conventionally, since a separate, large heat exchanger has been employed in a gasification complex facility to cool hot synthesis gas generated in a reactor, there are problems in that the gasification complex facility increases in size, and installation cost is increased.